Being pretty new to the TW, but an old school dirt biker, I immediately poured over all the forums looking for the "right upgrades". I was pretty close to drilling out the core (1" hole 7" down inside the muffler). But I was surprised that I found NO ONE reported a positive outcome for changing out or even modifying the exhaust. They did say that every mod did increase the noise more than they liked. That told me modifying the exhaust wasn't a place that would yield good results.
I've done the usual carb mods (fuel mixture screw, jet, shims) to great success, and suggest you start there. The TW needs to breathe better, but it is so small that you can give it too much air, which can be a bad thing. I added a short 45 degree extension (you can find the mod on the forum) to the muffler's outlet. I believe the TW really likes the extra added back-pressure which sort of validates leaving the exhaust stock. It does purr a very sweet tune and runs really smooth.
For my money, I'm leaving the exhaust and air box stock and keeping the money.
I've done the usual carb mods (fuel mixture screw, jet, shims) to great success, and suggest you start there. The TW needs to breathe better, but it is so small that you can give it too much air, which can be a bad thing. I added a short 45 degree extension (you can find the mod on the forum) to the muffler's outlet. I believe the TW really likes the extra added back-pressure which sort of validates leaving the exhaust stock. It does purr a very sweet tune and runs really smooth.
For my money, I'm leaving the exhaust and air box stock and keeping the money.
